The present invention relates to a nozzle for a liquid injection device, a method for producing the nozzle, and a liquid injection device having the nozzle.
There has been hitherto known a liquid injection device as a device for discharging liquid as fine particles. For example, such a device is disclosed in Japanese Patent Laid-Open No. 6-40030. However, in some cases, air is compulsorily sent to a portion around a liquid injection hole, i.e., a tip of a nozzle for the purpose of evaporation or drying of injected liquid, concentration of solid components contained in the liquid, promotion of momentary movement of the injected liquid, or the like. Since a tip part of the nozzle is formed to have the same height as an outer frame of a unitarily molded device as shown in FIG. 3 in each of these devices, liquid injected along the outer frame is prone to form a thin film due to its own surface tension.
Once such a film is formed, the film acts mutually with liquid subsequently injected. Therefore, injected particles become large or small due to evaporation of the injected liquid in the periphery of the nozzle, scattering of injected particles, or an integrated action of these phenomena, and thereby injection of liquid as uniform particles is hindered. Under certain circumstances, injected liquid forming a film is dried and sticks to the periphery of a hole of the nozzle. In such a case, since a nozzle has a very small caliber by nature, dried injected liquid adheres to a tip part of the nozzle, and thereby smooth injection operation of liquid is hindered. In the worst case, the nozzle is completely clogged, and thereby there is caused a problem of incapable desired operation, for example, incapable production of a powder having an aimed particle size in the case of producing a dried powder.
Therefore, the present invention aims to provide a ceramic nozzle for a liquid injection device which is free from the problems that injection of liquid as uniform particles is hindered because of evaporation of the injected liquid in the periphery of the nozzle, scattering of injected particles, or the like, due to adhesion of liquid in the periphery of a tip part of the nozzle; injected liquid is dried and adheres to a tip part of the nozzle, and thereby smooth injection operation of liquid is hindered; or that the nozzle is completely clogged, and thereby desired operation is hindered; and the like.
The present invention has been made in view of the aforementioned problems and has been completed by finding out that the above object can be achieved by forming a projected part in a tip part of a nozzle for a liquid injection device.
That is, as the first aspect of the present invention, there is provided a nozzle for a liquid injection device, wherein a tip part of the nozzle provides a projected part.
As the second aspect of the present invention, there is further provided a nozzle for a liquid injection device, wherein an internal surface of the projected part is tapered toward a narrowed injection port, and a cross-section perpendicular to a liquid injection direction of the projected part is almost circular.
As the third aspect of the present invention, there is furthermore provided a method for producing a nozzle having a projected part in a tip part, comprising:
disposing a ceramic green sheet (11) to be used as a bottom part of a liquid injection device to which a nozzle is attached between a die (2) and a stripper (3) storing a punch (4) therein,
moving the punch (4) to form a hole forming the nozzle in the green sheet (11),
disposing the green sheet between a die (2xe2x80x2) having a cavity having a reversed configuration of a projected part and a stripper (3xe2x80x2) storing a punch (5) therein so that the punch (5) is inserted in the green sheet in the direction opposite to the direction in which the punch (4) is inserted in the green sheet,
moving the punch (5) to obtain a configuration of the nozzle, and
baking the green sheet.
As the fourth aspect of the present invention, there is furthermore provided a method for producing a nozzle having a projected part in a tip part thereof, wherein the stripper (3) or the stripper (3xe2x80x2) mechanically stops just before the green sheet (11), and then only the punch (4) or the punch (5) is moved to machine the green sheet.
As the fifth aspect of the present invention, there is furthermore provided a method for producing a nozzle, wherein the green sheet is prepared by using a ceramic powder having an average particle diameter of 0.2 xcexcm-1.0 xcexcm.
There is furthermore provided a liquid injection device having a nozzle of the first or second aspect of the invention.